The objective of the project is to investigate the role of growth and differentiation factors in bone and cartilage. The projects currently under investigation with the salient findings are: 1) Isolation and purification of osteogenins from bone matrix. Osteogenins have been isolated and purified from bovine, porcine and human bone matrix. Osteogenin was purified by affinity chromatography on heparin Sepharose, hydroxyapatite and Sephacryl S-200. Bovine osteogenin was further purified by preparative SDS-gel electrophoresis. Osteogenin activity was localized in a zone between 30 and 40 k Da. Amino acid sequence of a number of tryptic peptides were determined. Current work is directed towards assessing structure-function relationships; 2) Production and characterization of antibodies to synthetic peptides. Amino and carboxy terminal and internal peptides have been synthesized and antisera elicited. These antisera are being systematically scrutinized by a battery of techniques; 3) Cloning and expression of osteogenis by recombinant DNA methods. Ostoegenin has been successfully cloned and currently attempts are being made to express in transient and stable expression systems; 4) Affinity of osteogenin, an extracellular bone matrix associated protein initiating bone differentiation, for lectins. Partially purified osteogenin binds to concanavalin A but not to wheat germ agglutins or soybean lectin. Osteogenin is a glycoprotein and concanavalin A Sepharose chromatography is a useful technique; 5) Purification of osteogenin form rat tooth matrix by heparin affinity chromatography; 6) Stimulation of the expression of osteogenic and chondrogenic phenotypes in vitro by osteogenin, and 7) Response of chick limb bud mesodermal cells to transforming growth factor beta-type 1. The significance of this investigation is in the realms of correction of craniofacial anomalies, oral surgery and fracture repair in orthopaedic surgery.